Various upper limb and other prosthesis systems have been designed, employing myoelectrically controlled and similarly controlled power units. The existing systems have been designed for movement of a specific joint of a prosthesis. Certain types of power units have been developed exclusively for elbow motion, whereas others have been developed exclusively for wrist motion and/or terminal device function. Conventional prosthesis systems must be extensively modified to be compatible with these power units. The appliance is therefore usually created and delivered as a complete unit. Only a limited number of styles and sizes of terminal devices or other conventional components are compatible with many of these currently available artificial limbs. Also, due to their complexity, specifically trained personnel are required for their fabrication, servicing and maintenance. In addition, their cost is high and their availability for general use is limited.
Therefore, there is a substantial need for a simplified externally powered prosthetic system which can be controlled by an EMG, or similar, signal to operate in a proportional mode to control either a hook/hand grasping assembly (terminal device) or an elbow flexion assembly using conventional terminal devices or other components which might be used as part of the total prosthesis.
More specifically, there is a substantial need for a simplified artificial arm structure including a pivoted upper arm element, a forearm element pivoted to the upper arm element to define an elbow joint, and a terminal device, such as a grasping hook assembly, carried by said forearm element, with driving means, such as a motor, to operate the elements, and suitable easily controlled means to selectively lock the various joints at times, whereby the user can perform a wide range of functions closely simulating those available with a normal arm.